#Dr-Volt #video #toread about #microscopy with a Blu-Ray laser. #hoarding #electronics
on 02026-08-24Another #Steve-Mould #video about #Gelsight #microscopy, which uses raking light from many angles inside a transparent gel pad to scan the surface topography of small objects in 3-D.
on 02026-08-11#Applied-Science #video using femtosecond lasers and electron #microscopy to slice carbonized insects in the chamber
on 02026-08-10#Geopolymers #video featuring Davidovits himself, from “2024 Geopolymer Camp”. He presents a lot of scanning electron #microscopy to support his claims about the chemical structures of geopolymers, but the flexural strength is still very low (apparently a new metakaolin boosts it from 10 MPa to 30 MPa) and I would have liked to see something like NMR spectroscopy or Raman spectroscopy or FT-IR spectroscopy to support his claims that the geopolymer structure is covalent rather than ionic (which he never really comes out and says explicitly). He goes on to try to sell his new book about ancient Bolivian and Easter Island geopolymers.
on 02026-01-13#paper on the #history of #Leeuwenhoek’s #microscopy; apparently he melted the end of a glass fiber to make his microscope lenses rather than grinding them.
on 02025-12-18#video #toread by #Breaking-Taps on laser scanning #microscopy
on 02025-06-22#video of #Applied-Science making LED-array Fourier #ptychography work for #microscopy. He explains a lot of things he tried that didn’t work.
on 02025-03-04#Veritasium #video of aspheric electron #microscopy using radially asymmetric magnetic lenses
on 02025-02-05the "OpenFlexure" DIY microscope #microscopy
on 02024-12-19discussion of the #OpenFlexure DIY microscope #microscopy
on 02024-12-19#video on #3D-printing an #STM for #microscopy. This is a unimorph disc type made from a piezo buzzer; he ruined several before switching to ultra-fine magnet wires and low-temperature solder (ChipQuik?). His kinematic mount seems to consist of three bearing balls, one in a V-groove, one on a flat glass surface, and one in some kind of a pit, each adjustable with a knurled screw. He seems to have used heat-set inserts to build his frame out of 3-D printed plastic — although PLA has the best TCE of common plastics, he’s using PA-CF, carbon fiber reinforced nylon, which ought to be pretty stable in the X and Y dimensions, like wood. (He mentions that many STMs are made out of Zerodur or similar glass-ceramic #materials.) Printed on a Bambu Lab X1 Carbon. The voiceover might be an AI reading a script because it mispronounces a lot of words and sometimes gets the prosody of sentences wrong, despite having a bog-standard GA accent. He put metal tape on the parts for EMI shielding; looks like aluminum flashing. To pre-amplify the nanoamps or picoamps signal from the tunneling current, he copied Dan Berard’s open-source STM preamp circuit, naturally using a current-to-voltage converter built around an op-amp, but I can’t tell which one. He shielded his cable to the probe and put the analog electronics in a Faraday cage to reduce EMI further, getting only about 10pA of noise. Berard’s #electronics design used an OPA124, but he says “The chips used in Dan’s design are hard to find these days.” When it comes to #microcontrollers #hardware, he’s using a Teensy 4.1. He’s using an aluminum plate and some rare-earth magnets to damp the oscillations of his stable platform. “This is the first atomic image captured by a 3-D printed scanning tunneling microscope.”
on 02024-09-28#Breaking-Taps #video about looking at #precision flat surfaces with atomic force #microscopy. His new gauge block has 12 nanometer RMS surface roughness with a total range of almost ±50nm over the 10μm square field of his AFM. A first-surface mirror is 3nm RMS with 36nm range. A λ/20 fused silica mirror blank (λ = 632.8nm) is 2nm RMS, 39nm range. A cheap glass microscope slide is 1.9nm RMS, 62nm range, mostly due to a few big peaks. A silicon wafer is 1.6nm RMS, 17nm range. And a piece of mica (!!!) is 530 picometers RMS, 8nm range.
on 02024-09-17#Breaking-Taps #video about #MEMS accelerometers. He uses a lot of electron #microscopy to show the #flexures and other #mechanisms, then makes macroscopic replicas with #3D-printing. I don’t understand the whole flexure layout, but I appreciate the effort. He says the “gyros” use the Coriolis force generated from resonant vibration, which changes their resonant frequency. I don’t know. #toread
on 02024-09-05#video on #manufacturing #optics by #machining pure copper (to eliminate inclusions enriched in other elements that can cause tearout) with a monocrystalline diamond cutter. Lots of footage from atomic force #microscopy and scanning electron microscopy. To eliminate 50μm steps between adjacent passes of the diamond milling cutter, he switched to 0rpm, just using his milling machine as a sort of shaper, and got the surface roughness down to about 13nm. #Breaking-Taps
on 02024-08-28#Steve-Mould #video on what I thought was scanning probe #microscopy but is actually deforming a gel and illuminating its opaque surface with a ring of six lights in front of a camera using the "photometric stereo technique" to measure things to ±4μm #precision.
on 02024-08-26Maxim Shusteff’s 02006 #AFM at MIT. #microscopy
on 02021-11-1102014 #AFM #microscopy by “whoand” (Dr. Edwin (En-Te) Hwu, Institute of Physics, Academia Sinica, Taipei, Taiwan) under GPL. “I am pleased to share with you that the DIY AFM is reported by the latest Nature Nanotechnology 10, 480 (2015) that the DIY AFM is assembled by junior high school student...” Using store-bought AFM probes, though. Uses four piezo buzzers instead of cutting one into quarters like Berard’s STM. Uses FR4 (?) circuit board material for stiffness. Concrete block on bicycle inner tube for vibration isolation.
on 02021-11-11why #STM #microscopy is usually done at ultra-high #vacuum (picotorrs). Handy chart: roughly XHV = attotorrs, UHV = picotorrs, HV = nanotorrs, MV = microtorrs, rough vacuum = millitorrs. “At a pressure of 1×10⁻⁶ Torr the crystal surface will be contaminated with a monolayer of gas in 1 second.”
on 02021-11-11#SEM #microscopy #introduction, covering issues like critical-point drying, field emission vs. thermionic, magnetic astigmatism, secondary electron noise, #vacuum, etc.
on 02021-11-11David Berard’s #STM #hardware (and software) for #nanotech #microscopy in air, using the software Gwyddion. Won’t work on most metals because of the oxide coating.
on 02021-11-10"STED microscopy" is differential #microscopy by selectively depleting fluorophores, getting resolution down to 2.4nm
on 02021-01-13#pdf #paper on “Diffraction-unlimited imaging: from pretty pictures to hard numbers”. Advances in #microscopy allowing optical imaging at nanometer scale, i.e. deep subwavelength: “optical sub-diffraction microscopy”.
on 02016-06-27